This invention relates generally to the field of optical communications and more specifically to method of establishing communication paths, or calls, in an all optical wavelength division multiplexed network.
Telecommunication based networks were developed as an evolution of the technology created to transport a basic phone call; a 64K digital data stream containing voice. T1's were later developed to transport these calls in bulk, T3's after that, and so on. Later, packet technology developed by ARPA (Advanced Research Projects Agency) was adapted to run across these existing facilities for wide spread use by the defense department. Once the value of packet based networking was realized, wide area technology was born, and evolved quickly into the technologies we are familiar with today such as IP, Ethernet, MPLS, ATM, Frame Relay, SONET, and most recently WDM.
All past and present optical communication technologies utilize a given wavelength, usually 1310 nm, to act as a carrier to facilitate a given type of communication, such as MPLS, Frame Relay, SONET, ATM, Gigabit Ethernet, etc . . . Each of these technologies utilize their own ‘language’ so to speak, to carry out communication functions. SONET uses a 51.84 Mb frame structure referred to as a STS-1 to act as a data transport, ATM utilizes a 53-byte cell to transport data, Frame Relay and Ethernet utilize variable length containers to act as a data transport and are incompatible with each other, as are all of these data transports. All current technologies are also built at the hardware level to conform to specific bit-rate or speeds; for example, SONET typically runs at 155 Mbps, 622 Mbps, 2.488 Gbps and so on in exponential multiples of 51.84 Mbps.
Typically these network infrastructures (MPLS, Frame Relay, SONET, ATM, Gigabit Ethernet, etc . . . ) are built and operated individually and independently. Whenever there is a need to connect or interoperate two or more of these technologies, special considerations must be made, and special hardware must be purchased to allow for conversions between the different technologies. This, in itself, can be a major problem by adding allot of extra complexity to the network, as well as major cost expense.
A recent advancement in communication technology known as Dense Wavelength Division Multiplexing (DWDM), provides significant bandwidth gains and allows incompatible technologies to share a common fiber optic medium by employing multiple wavelengths (or different colors of light) over the same fiber optic cable. Placing different wavelengths of light together over the same fiber optic medium allows us to take advantage of a basic principle of physics. That is, that light of different wavelengths will not interfere, or corrupt each other. This allows us to utilize each wavelength independently of the next. Today we utilize these wavelengths by operating different technologies across individual wavelengths such as SONET on one wavelength, and ATM on another; in this way they can be transported together and not interfere with each other. Another way of utilizing these wavelengths is to run multiple instances of the same technology over the different wavelengths for the purpose of gaining additional bandwidth without having to add additional fiber optic cable to the existing network.
The latest advancement in DWDM technology is known as the Optical Cross Connect (OCX), and allows near real-time switching of wavelengths similar to the way an ATM switch switches cells amongst PVC's. Wavelengths can be switched amongst a number of ports inside a given OCX switch. This is most commonly done now by extremely small mirrors and Micro Electro Mechanical Systems (MEMS) technology. This technology will eventually allow DWDM based networks to be dynamically reconfigured and virtually rebuilt in real time without physical changes to the network itself.
It is the advent of this new technology (OCX) that makes this method possible. Currently there are no methods developed for dynamically utilizing this new technology in a brand new way to create a totally new type of communication system or network. The closest way to accomplish what this method accomplishes today, would be to utilize current and past routing protocols, such as OSPF, RIP, BGP, PNNI, etc . . . to construct communication pathways across a network utilizing OCX switches, and this would limit the overall functionality of the network to operating as they always have; utilizing fixed bit-rates, and incompatible technologies because these protocols were designed for specific technologies. As previously mentioned, past and current technologies are built upon the 64 k digital voice circuit also known as the DS0 (Digital Signaling Level 0). This presents significant limitations in light of what can be accomplished if this new technology (OCX) is utilized in a new way without the limitations of technology that is over 100 years old.
Technologies today (MPLS, ATM,SONET, Frame Relay, Gigabit Ethernet, etc..) all have several things in common; (1) they are bit-rate dependant (only operate at given speeds), (2) they utilize structured transports (like the STS-1, or the Cell) that are incompatible with each other, (3) their transports waste valuable bandwidth, sometimes up to 20%, in order to keep track of user data, identify payload types, and transport signaling or network management information, and finally (3), they are all digital.
By utilizing this method to construct communication paths in a network built on all-optical DWDM and OCX technology, we can create a new type of communication infrastructure, one that does not suffer from these limitations. This new infrastructure is simply a network of light-waves passed around a fiber-optic network that employees no O-E-O (Optical to Electrical to Optical) technology. A path of light is constructed and utilized as a carrier for whatever type of communication is needed. These optical carriers are constructed between communicating devices and allow any type of communication to be carried out across them, analog or digital. This new infrastructure is transparent to the end user devices attached to it, so the core network itself has no bit rate limitations, and is also blind to the protocol utilizing it such as SONET, ATM, MPLS, etc..
This method combined with the proper technology creates a truly open and generic method of communications that be created to support past, present, and future optical communication needs.
Objects and Advantages:
The primary object of the invention is to provide a method of establishing communication that allows for both digital and analog communication methods.
Another object of the invention is to provide a method of establishing communication that does not limit the speed or bit rate of any communication.
Another object of the invention is to provide a method of establishing communication that allows any given individual communication to be undetectable to any other given communication.
Another object of the invention is to provide a method of establishing communication that will act as a means or carrier for other optical communication technologies, and therefore be backward compatible with other existing optical communication technologies.
A further object of the invention is to provide a method of establishing communication that reduces or removes the need for additional communication information to be added to a primary communication to facilitate, identify, or track the primary communication.
Other objects and advantages of the present invention will become apparent from the following descriptions, taken in connection with the accompanying drawings, wherein, by way of illustration and example, an embodiment of the present invention is disclosed.